Under DC conditions, superconducting magnets have minimal losses and are extremely stable, and thus provide an efficient device for storing energy. A principal application for Superconducting Magnetic Energy Storage (SMES) is to provide intermittent power, especially for applications requiring limited duration of high peak power. Unlike battery back-up systems, the energy storage capacity of a SMES does not deteriorate over time. A further important advantage is that a SMES device can discharge to, or be charged from, an electric utility power grid at exceptionally high power rates with very high round-trip efficiency.
Superconducting Magnetic Energy Storage (SMES) systems provide rapid response to charge and discharge operations but, unlike other technologies, the energy available is independent of the discharge rate. The system is deployable and can be scaled from small units to very large units and, unlike other technologies, the unit cost per unit stored energy decreases with increasing size. The scalability of this technology offers the advantage of being able to cover a large spectrum of the energy-power requirements for storage systems, from less than a megawatt (MW) to thousands of MW with storage times spanning from minutes to hours, and fast discharge times, on the order of fractions of a second.
In recent years, there have been major advances in both low-temperature superconductors (LTS), and in the newer high-temperature superconductors (HTS). The Department of Energy programs in electric energy systems, magnetic confinement fusion technology, and accelerator technology for high-energy physics (HEP), have been instrumental in advancing HTS technology.
It would be advantageous if it were possible to take advantage of these large investments and apply them to electricity storage systems for electric utility power grids.